import java.util.Scanner;

public class 素数判定 {
    public static void main(String[] args) {
        Scanner scanner=new Scanner(System.in);
        int n= scanner.nextInt();
        for (int i = 2; i < n ; i++) {
            if(n%i==0){
                System.out.println("不是素数");
              break;

            }
            if(i==n-1){
               System.out.println("是素数");
           }
        }



    }
}
